The Open Geospatial Consortium (OGC) is an international
consortium of more than 250 companies, agencies, and universities
participating in the development of publicly available conceptual
solutions that can be useful with all kinds of applications that
manage spatial data.

The Open Geospatial Consortium publishes the
OpenGIS® Implementation Standard for Geographic
information - Simple feature access - Part 2: SQL
option, a document that proposes several conceptual
ways for extending an SQL RDBMS to support spatial data. This
specification is available from the OGC website at
http://www.opengeospatial.org/standards/sfs.

Following the OGC specification, MySQL implements spatial
extensions as a subset of the SQL with
Geometry Types environment. This term refers to an SQL
environment that has been extended with a set of geometry types. A
geometry-valued SQL column is implemented as a column that has a
geometry type. The specification describes a set of SQL geometry
types, as well as functions on those types to create and analyze
geometry values.

The spatial data types and functions are available for
MyISAM,
InnoDB,
NDB, and
ARCHIVE tables. For indexing spatial
columns, MyISAM and InnoDB
support both SPATIAL and
non-SPATIAL indexes. The other storage engines
support non-SPATIAL indexes, as described in
Section 13.1.14, “CREATE INDEX Syntax”.

A geographic feature is anything
in the world that has a location. A feature can be:

An entity. For example, a mountain, a pond, a city.

A space. For example, town district, the tropics.

A definable location. For example, a crossroad, as a
particular place where two streets intersect.

Some documents use the term geospatial
feature to refer to geographic features.

Geometry is another word that
denotes a geographic feature. Originally the word
geometry meant measurement of the
earth. Another meaning comes from cartography, referring to the
geometric features that cartographers use to map the world.

The discussion here considers these terms synonymous:
geographic feature,
geospatial feature,
feature, or
geometry. The term most commonly
used is geometry, defined as
a point or an aggregate of points representing anything
in the world that has a location.

MySQL GIS Conformance and Compatibility

MySQL does not implement the following GIS features:

Additional Metadata Views

OpenGIS specifications propose several additional metadata
views. For example, a system view named
GEOMETRY_COLUMNS contains a description of
geometry columns, one row for each geometry column in the
database.

The OpenGIS function Length()
on LineString and
MultiLineString should be called in MySQL
as ST_Length()

The problem is that there is an existing SQL function
Length() that calculates the
length of string values, and sometimes it is not possible to
distinguish whether the function is called in a textual or
spatial context.

Additional Resources

The Open Geospatial Consortium publishes the
OpenGIS® Implementation Standard for Geographic
information - Simple feature access - Part 2: SQL
option, a document that proposes several
conceptual ways for extending an SQL RDBMS to support spatial
data. The Open Geospatial Consortium (OGC) maintains a website
at http://www.opengeospatial.org/. The
specification is available there at
http://www.opengeospatial.org/standards/sfs. It
contains additional information relevant to the material here.